Stormwater Management: What Municipalities Need to Know
Stormwater management doesn't always get the attention that water or wastewater projects do. But for municipalities across eastern Washington, it's a growing part of the infrastructure conversation.
Aging systems, increasing regulatory requirements, and the cost of reactive repairs are pushing more communities to take a closer look at what they have and what they need. This guide covers the basics: what stormwater management involves, what Washington municipalities are required to do, and how to approach planning when resources are limited.
Why Stormwater Matters in the Inland Northwest
In the Inland Northwest, rainfall and snowmelt do important work. They replenish aquifers, support irrigation, generate energy, and sustain the natural ecosystem that communities depend on.
The challenge comes when that water runs off hard surfaces. Roads, parking lots, rooftops, and developed watersheds change how water moves. Instead of soaking into the ground, it moves fast, picks up pollutants, and puts pressure on drainage systems that weren't always designed to handle it.
Managing that runoff well protects community infrastructure, reduces flooding risk, and keeps waterways healthier. When it's managed poorly, the costs show up in road damage, property flooding, erosion, and water quality problems that are far more expensive to address after the fact.
What a Stormwater System Actually Does
A municipal stormwater system collects and moves runoff away from developed areas. It includes storm drains, pipes, ditches, channels, detention basins, and related infrastructure that routes water to a safe discharge point.
Beyond basic conveyance, stormwater management also includes controlling water quality. Runoff picks up sediment, oil, and other pollutants as it moves across developed surfaces. Best management practices, commonly called BMPs, are designed to reduce those pollutants before water reaches streams and rivers.
For many smaller communities, the stormwater system grew over decades without a coordinated plan. Understanding what you have, where it goes, and how well it performs is usually the starting point for any meaningful improvement.
What Washington Municipalities Are Required to Do
Washington State regulates municipal stormwater through the Department of Ecology under the federal Clean Water Act. Communities that meet certain size and discharge criteria are required to obtain a municipal stormwater permit, commonly referred to as an MS4 permit.
The Eastern Washington Phase II Municipal Stormwater Permit applies to regulated communities in our region. It sets requirements around public education, illicit discharge detection, construction site runoff control, and long-term operation and maintenance of stormwater systems.
Not every small municipality in eastern Washington is regulated under this permit. But many are, and the requirements have grown more specific over time. If your community is unsure about its permit status or current obligations, that's a good place to start the conversation with an engineering firm familiar with Washington DOE requirements.
The Case for Planning Ahead
Many communities across eastern Washington are managing stormwater systems that were built incrementally, without a comprehensive plan. Pipes and ditches were added as development happened, not as part of a coordinated design.
That works until it doesn't. When a system reaches its capacity, or when a flood event reveals gaps in coverage, repairs become urgent and expensive. Reactive fixes also tend to address symptoms without solving the underlying problem.
Planning ahead changes that dynamic. A stormwater master plan gives a municipality a clear picture of what it has, where the deficiencies are, and what improvements are needed in what order. It also creates a framework for phasing work over time and positioning projects for available funding.
Communities that plan ahead have more options. They can sequence improvements strategically, apply for grants before a crisis forces their hand, and manage capital costs in a way that works within their budget.
What Stormwater Planning Actually Involves
A stormwater planning process typically starts with understanding the existing system. That means mapping what's in the ground, evaluating the capacity of existing facilities, and identifying where the system is underperforming.
From there, the work moves into analysis. Hydrologic and hydraulic modeling helps engineers understand how water moves through the system under different conditions and where improvements would have the most impact.
Other elements of a thorough stormwater planning process include floodplain and floodway analysis for community development and FEMA compliance, stormwater quality design, permit assistance, and public involvement when projects affect neighborhoods or local waterways.
Varela has completed stormwater projects for communities across eastern Washington, including system assessments and improvements in Tonasket, a stormwater utility setup in Othello, and stormwater planning and improvements in Republic. Each project started with a clear understanding of the community's existing conditions and a realistic plan for what could be improved and how.
Funding Is Available for Stormwater Projects
Stormwater improvements are often eligible for grant and loan funding through state and federal programs. Many communities don't realize this until they're already deep into a project, which means they miss the window to apply.
Varela has helped communities across the Inland Northwest secure funding for stormwater projects alongside water, wastewater, and transportation work. Getting an engineering firm involved early in the planning process gives your community more time to build a funding strategy before construction costs have to come entirely from local sources.
If your municipality is dealing with aging stormwater infrastructure, new compliance questions, or a system that hasn't been formally evaluated in years, Varela can help you figure out where to start. Get in touch to talk through your community's situation.
